T. Hirai

Refraction contrast 11×-magnified X-ray imaging of large objects by MIRRORCLE-type table-top synchrotron

The high-quality aspects of magnified X-ray images recorded using MIRRORCLE-6X are reported. MIRRORCLE-6X is inherently suitable for hard X-ray imaging owing to its magnified projection X-ray imaging, micrometre-size X-ray source point, wide radiation emission angle, X-ray spectrum ranging from 10 keV to 6 MeV, natural refraction contrast imaging and high flux output. Images produced with 11x geometrical magnification display a sharply enhanced edge effect when generated using a 25 microm rod electron target. Image contrast is enhanced 2x owing to refraction when compared with absorption contrast images. An imitation tumour implanted in a human chest phantom was made clearly visible by using edge enhancement on images. Soft tissue becomes highly visible as a natural consequence of refraction contrast when using hard X-rays for imaging. The authors believe that novel imaging provided by MIRRORCLE makes it a superior instrument for medical diagnosis.

Novel Edge‐Enhanced X‐ray Imaging by MIRRORCLE

Brilliant hard x‐rays are produced by the portable synchrotron named MIRRORCLE. The x‐ray images taken by MIRRORCLE show the enhanced edge effect even with contact imaging. Bodies composed of light elements are distinguished in spite of its dominated hard x‐ray components. The imaging mechanism involved, which is different from the phase contrast, is studied in this paper. It is found that the edge effect is partly due to the micron order x‐ray source spot size, and MeV region hard x‐rays.

Protein Crystallography Beam Line at MIRRORCLE

A Protein crystallography beam line using MIRRORCLE‐6X, which is a compact synchrotron for hard x‐ray production, is under construction. Since MIRRORCLE‐6X provides hard x‐ray with high brightness, it is suitable for x‐ray source of accurate protein crystallography research in a small laboratory.The divergent x‐ray emitted from a target is focused by a condensing mirror. The mirrors used for the condensing mirror are a multi layer mirror of Wolter type and a rotating ellipsoidal mirror. Photon energies dispersed by them are set to the K‐edge of Zn and of Se, respectively. The flux at a focusing point is expected to be 103 ∼ 104 times larger than that without the condensing mirror. The focusing size is less than 100 μm of diameter. The x‐ray after the mirror is transformed to parallel beam using a Fresnel zone plate and irradiated on a protein crystal. The diffraction figure is detected by the an imaging‐plate detector.

Magnified NDI Imaging Using MIRRORCLE‐Type Table‐Top Synchrotron

We report that the magnified imaging using the portable synchrotron named MIRRORCLE has unique advantages for non‐destructive inspection (NDI) of some products. This machine is a high energy x‐ray source which can have a micron‐sized point source, which is different from the conventional synchrotron, linear accelerator and the x‐ray tube. The images produced with micron‐sized point source and wide spectrum can display in detail the industrial products containing several materials in detail. The obtained x‐ray images characterization is expected to provide a new tool for NDI of industrial products.

Problem of radiation safety in the diagnosis using MIRRORCLE

We have evaluated the absorption dose by simulation in a phantom irradiated by the X‐ray from the 6MeV electron synchrotron MIRRORCLE‐6X. Comparison with the dose by the X‐ray from a 100keV X‐ray tube was made. It shows that the averaged dose integrated over the phantom to make one flame of the X‐ray image in the case of MIRRORCLE‐6X is much smaller than that in the case of the X‐ray. We have also measured the dose using MIRRORCLE‐6X under the various conditions. We could confirmed this results experimentally by observing dose at the surface, although it was slightly higher than expected.

Novel Edge‐Enhanced X‐ray Imaging Utilizing MIRRORCLE

Brilliant hard X‐rays are produced by the portable synchrotron named MIRRORCLE. The X‐ray images taken by MIRRORCLE show enhanced edge effect even with contact imaging. Bodies composed of soft tissues are distinguished in spite of the predominantly hard X‐ray components. The imaging mechanism, which is different from the phase contrast, was studied. It was found that the edge effect is partly due to the micron order x‐ray source spot size, and MeV region hard X‐rays. The characteristic of the medical diagnosis X‐ray images and nondestructive inspection X‐ray images taken by MIRRORCLE are studied in this paper.

Magnified 3D‐CT System Using the Portable Synchrotron “MIRRORCLE‐6X”

The portable synchrotron MERRORCLE‐6X is a novel x‐ray source suitable for hard x‐ray imaging. Highly brilliant x‐rays are generated by MIRRORCLE‐6X in the shape of cone from a source with micron size. We obtained images with high magnification and high resolution by these x‐rays, and found that they can be utilized for medical imaging. Recently, we started to perform ideal 3‐dimentional computed tomography (3D‐CT) based on the Feldkamp algorithm, which is the most popular reconstruction algorithm for a cone beam CT, using a flat panel detector. Therefore, we developed a magnified 3D‐CT system of high quality using MIRRORCLE‐6X.

Development of 3D‐CT System Using MIRRORCLE‐6X

The technique of computed tomography (CT) has been used in various fields, such as medical, non‐destructive testing (NDT), baggage checking, etc. A 3D‐CT system based on the portable synchrotron “MIRRORCLE”‐series will be a novel instrument for these fields. The hard x‐rays generated from the “MIRRORCLE” have a wide energy spectrum. Light and thin materials create absorption and refraction contrast in x‐ray images by the lower energy component (< 60 keV), and heavy and thick materials create absorption contrast by the higher energy component. In addition, images with higher resolutions can be obtained using “MIRRORCLE” with a small source size of micron order. Thus, high resolution 3D‐CT images of specimens containing both light and heavy materials can be obtained using “MIRRORCLE” and a 2D‐detector with a wide dynamic range. In this paper, the development and output of a 3D‐CT system using the “MIRRORCLE‐6X” and a flat panel detector are reported.A 3D image of a piece of concrete was obtained. The detect...

Medical X-ray Imaging by MIRRORCLE-6X

The portable synchrotron “MIRRORCLE‐6X” provides hard x‐rays with high brightness and wide energy spectrum ranging from 10–300 keV, emitted from a micron‐sized source, with wide divergence of ± 85 mrad. Correspondingly, images obtained using the “MIRRORCLE‐6X” showed significantly improved characteristics compared to conventional x‐ray tube images, namely, improved refraction contrast, high resolution, and high magnification. Thus, the “MIRRORCLE‐6X” is considered to be a novel medical imaging source.A magnified image of a chest phantom, wherein a urethane ball of 8 mm diameter was implanted as an imitation of a cancer, was obtained. The detector used was an imaging‐plate (Fujifilm imaging plate, FCR ST‐IV) with 150 μm pixel size. The phantom and the detector were respectively set at 50 cm and 540 cm from the x‐ray source, so that the magnification was 10.8x. The x‐ray source was a Cu 25 μm rod. The resolution was about 25 μm. Images with such high resolution and magnification cannot be obtained by conven...

Refraction Contrast Imaging by Using MIRRORCLE-Type Tabletop Synchrotron

MIRRORCLE type tabletop synchrotron is suitable for magnified hard x‐ray imaging due to its micron size x‐ray source, wide radiation angle, x‐ray spectrum ranging from a few keV to 6 MeV and high flux output. It is known that the magnified imaging by a micron size x‐ray source provides a high spatial resolution image, and a sharply enhanced edge effect for weakly absorbing objects. This x‐ray imaging technique is known as a phase‐contrast imaging. In this work, we performed a phase contrast imaging of a simple shape objects using an imaging plate for studying the characteristics of the edge enhancement by MIRRORCLE. It turns out that the edge effect is enhanced for higher magnification and smaller source size. The characteristics of the edge effect can be explained by using the refraction effect. Furthermore, the refraction contrast is enhanced when the imaging system resolution is decreased. By using MIRRORCLE, we can obtain refractive‐contrast images of objects as large as human. The magnified x‐ray ima...